Experimental Comparison of Power Conversion Loss with Different PWM Strategies for STATCOM Application

Bus clamping PWM techniques are known for their high DC bus utilization. In BCPWM one of the phases will be clamped over one-third portion of fundamental period. This results in a reduction in average switching frequency and power loss compared to the conventional space-vector PWM (CSVPWM). The switching loss in BCPWM is a strong function of the power factor. For high power factor BCPWM has proven to be having low power conversion loss than conventional PWM (CSVPWM). But at low power factors, e.g., zero power factor lag or lead, the reduction in power conversion loss is less. This paper presents an experimental evaluation of different BCPWM methods for STATCOM application in terms of power conversion loss at different power levels between 100 kVA and 150 kVA. Further, these methods are compared with CSVPWM for reduced and same average switching frequencies. For STATCOM application, 30° clamp PWM turns out to be the best among the PWM methods considered.